1. Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061;
2. Department of Mechanical Engineering, Universidad de Guanajuato, Salamanca, Guanajuato 36885, Mexico e-mails: ;
3. Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061 e-mail:
4. Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061
5. John and Willie Leone Family Department of Energy and Mineral Engineering, The Pennsylvania State University, University Park, PA 16802
6. Bradley Department of Electrical
and Computer Engineering, Northern Virginia Center, Virginia Tech, Falls Church, VA 22043